895
FXUS62 KGSP 281443
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1043 AM EDT Sat Jun 28 2025

.SYNOPSIS...
Temperatures near normal through the the first half of next week.
Expect afternoon and evening showers and thunderstorms each day.  A
weak cold front may reach the area by Tuesday with temperatures
warming afterwards.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1040 AM EDT Saturday: 12Z RAOBs and mesoanalysis show a very
unstable air mass remains over the area today with little to no bulk
shear; however, moisture is deeper with less mid level dry air and
DCAPE. That said, there is still DCAPE and sfc delta theta-e, so any
storm that can become tall enough could produce a damaging down
burst. Steering flow is again from the light SE today, so heavy
rainfall is possible where training can develop or cells anchor on
SE facing slopes. The forecast generally has this covered, so only
some relatively minor changes and/or fine tuning.

Otherwise, rinse and repeat as broad flow and the more typical
summertime pattern continues. The Bermuda High off to the east
stretches a bit westward and allows southerly flow to remain. This
keeps a slow uptick of moisture advecting into the area. Guidance
has PWATs in the 1.5-1.75 range, especially east of the mountains,
maintaining reasonable summer dewpoints in the upper 60s and very
low 70s. Meanwhile overnight, a few areas could see some patchy low-
level stratus or fog near daybreak though confidence is lower given
the amount of cloud debris from decaying storms. If any should
develop, expect it to clear up by daybreak. As for Saturday, expect
another afternoon of pop-up convection, typical for this time of
year. Plenty of instability once again and a stout inverted-V,
supporting near 1000 J/kg of dCAPE, giving way for an environment
capable of downbursts with any storm that develops. Given the calmer
winds aloft, any storm that can form will lack a steering ability
and are expected to be of the ordinary kind. Cannot rule out some
strong winds with any storm that collapses, but it`s the season for
diurnal convection. Most of the storms should weaken into Saturday
evening as peak heating ceases. Depending on what areas can get
rain, there is a chance for some more low-level stratus and patchy
fog again tonight, especially in the mountain valleys. As far as
temperatures, low 90s east of the mountains and overnight lows
dipping into the low 70s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 240 am Saturday: Typical summer-time pattern will remain
in place over the Southeast through the period, with a weakness
in the subtropical ridge atop the region, and southerly flow
around the western periphery of a Bermuda high supporting abundant
moisture... with precipitable water values of around 1.75" expected
through the period. The synoptic pattern will be supportive of
convective development, with elevated moisture and seasonal levels
of instability expected to result in above-normal coverage of
diurnal showers and storms each afternoon. PoPs are generally
advertised in the 60-70% range across the mountains, and between 40
and 50% across the remainder of the forecast area. Weak wind shear
combined with adequate instability will limit any severe storm
potential to a few brief pulse storms. The larger concern will
probably involve a locally heavy...possibly excessive rainfall
threat in light of high moisture levels and very slow cell movement
of around 5 kts. Max temps will be around normal through the period.
Min temps will remain several degrees above climo in light of
elevated surface dewpoints.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 305 am Saturday: A weakness in the subtropical ridge will
become displaced by more of a upper bona fide trough from the
Mid-Atlantic into the Carolinas early in the extended, as a
series of short wave troughs traverse the northeast quadrant of
the Conus and/or southeast Canada. Attendant weak frontal zone
is forecast to drop into the forecast area on Tuesday...providing
a focus for another day of enhanced diurnal convection...with at
least likely PoPs advertised for the bulk of the CWA during the
afternoon. Slight acceleration of the mid-level flow may improve
shear profiles enough to support more in the way of convective
clustering, combining higher coverage/more targets of opportunity
to allow for an uptick in the severe storm threat, while the threat
for locally excessive rainfall will also continue.

Confidence is gradually increasing that the surface boundary will
make enough of a push into the region to allow lower theta-E to
filter into the CWA for the latter half of the week. This may not
be enough to completely eliminate the convective potential Wed-Fri,
but diurnal convective coverage is expected to at least diminish
to more typical early summer levels...possibly less than that by
Thu/Fri. Temperatures are forecast to remain slightly above climo
through the period.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: VFR conditions prevail for most sites through
the TAF period. Mainly cirrus this morning with Cu developing this
afternoon. SW winds through the day most locations. NW to start at
KAVL becoming S for the afternoon. Another round of
afternoon/evening showers and TSRA so PROB30s at sites east of the
mountains. Higher chances and better confidence at KAVL and KHKY so
went with a TEMPO. Once the evening concludes, winds become calm/VRB
once again. If KAVL gets more rain, than expect a few hours at the
end of the TAF for more BR/FG with IFR/LIFR restrictions.

Outlook: Daily chances for afternoon and evening showers and
thunderstorms into next week. Fog and/or low stratus possible
each morning in the usual mountain valleys as well as near lakes
and rivers.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$

SYNOPSIS...CP
NEAR TERM...CP/RWH
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...CP/RWH